Synthesis, crystal structures and magnetic properties of a 1D chain based on trinuclear Cu subunits and a Cu4Dy2 complex

A one-dimensional (1D) chain [Cu-3(HL)(2)(N-3)(Mtta)](n)center dot 0.5CH(3)CN (1, H3L = 2-((2-hydroxybenzylidene)amino) propane-1,3-diol and Mtta = 5-methyl tetrazolate) and a Cu4Dy2 complex [Cu4Dy2{(py)(2)CO2}(2){(py)(2)C(OH) O}(2)(CH3COO)(4)(N-3)(4)]center dot 3CH(3)CN (2, (py)(2)C(OH)(2) = the gem-diol form of di-2-pyridyl ketone) were obtained by the assemblies of the H3L ligand and Dy(NO3)(3)center dot 5H(2)O with copper nitrate or with copper acetate and di-2-pyridyl ketone under the MeCN solution containing triethylamine or containing NaOH. In 1, three Cu-II ions were linked into a trinuclear Cu unit by three neighboring N atoms of Mtta ligand and two alkoxido-type O atoms from two HL2- ligands, then these units were further linked into a one-dimensional (1D) chain by two phenoxido O atoms from two HL2- ligands. In 2, two CuII and two Dy-III ions formed a butterfly-type topology, which was further linked another two Cu-II by the O atoms from (py)(2)CO22- or from acetate ligands. Magnetic studies indicated that, in 1, the magnetic coupling through the paths of Cu-N-N-Cu and Cu-O-alkoxido-Cu is antiferromagnetic (J(1) = -14.81 cm(-1)), and its value was first determined in the polynuclear Cu complexes containing Mtta ligand. However, the magnetic coupling through the path of Cu-O-phenoxido-Cu is ferromagnetic (J(2) = 24.61 cm(-1)). Magnetic studies revealed that 1 exhibits slow magnetic relaxation behavior, with an energy barrier U-eff of 6.06 K. The orientations of the easy magnetization axes of Dy-III ions in 2 was estimated by Magellan program, indicating that the easy axes of Dy-III in 2 are roughly aligned along alkoxido-type O atoms (O3 and O3a), which is slightly longer than other Dy-O distances.

Automated summary

By assembling different ligands, copper-nickel mixtures with different structures can be synthesized, exhibiting various magnetic coupling pathways such as antiferromagnetic and ferromagnetic interactions, along with slow magnetic relaxation behavior.